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WickWërks Tech Talk

Choosing the Right Gears

What gears should I ride?  How do I choose?

“Hey, my buddy Joe rides a 38 and loves it, so I think I should get that.”  Sound familiar?  I’ve over heard that kind of conversation many times, and I’m amazed.  It may be the Engineer in me — or it may be the Cycling Coach in me — or it may be familiarity with the subject — but  Whatever!   Gear ratios should be personal.

Why?  The right range of gears — fit to your physiology — will make you faster, and make your rides more enjoyable.

Interestingly, we make gearing choices all the time without thinking about it.  Check it out on a group ride — look at the various pedaling speeds while the group is traveling in the same place at the same velocity.  It’s fun to see.

In the past gearing was more “standard”.  Mountain bikes had triples.  Road bikes were “Compact” or “Standard”.  Cyclocross was road equipment with smaller chainrings.  Now, more options are available, but because many options are narrower in overall ratio range, it becomes especially important for us, as cyclists, to understand the importance, and the effects.

 

Racing:  Bicycle racers often focus on light weight and trendy rather than on efficiency.  This often gives slower race times, even if it’s lighter.  Yes, weight is important, but even more important is operating at your physiological optimum.  If gears are too low, you spin out; If gears are too high, you fatigue quicker.  (See this post for an example of breaking tradition for better performance.)

Personalize Your Gears:

Let’s set the stage for some personal assessment to choose YOUR gearing.  It’s not complicated, but it is important.

Starting with your current bicycle gearing and thinking about riding you do, follow these flow charts for an assessment.  (You may need to watch what you do while riding several times, because most people are not super aware of what they actually do when riding.)  We’ll look first at low gears, then at high ones.  Finally, we’ll combine results and discuss total ratio span.

To make the charts effective, take note of how you place yourself on the Frequency axis of each chart.  It’s subjective, for sure, and where you put yourself on the frequency scale will, in part, determine how much (if any) of a change in gearing to consider.  It’s not a simple up or down question — it’s a “how much?” question, and it requires some honest reasoning.

[ For Cycle-aholics (like me) try this exercise for each of your bikes (road, mountain, cyclocross). ]

Flow Chart 1:

Choosing Low Gears

Reasoning:   If you find yourself frequently using the biggest 2 or 3 cassette cogs — especially if you sometimes wish for a lower gear — then you’re probably geared too high.  See discussion about making changes (below).

Flow Chart 2:

Choosing High Gears

Reasoning:   If you find yourself mostly at the smaller end of the cassette — especially if you sometimes wish for a higher gear — then you’re probably geared too low.  See discussion about making changes (below).

 

The chart concepts make perfect sense, but usually we just don’t think about it.

Adjustments in gear ratio are easy to understand.  Bigger gears in front, and/or smaller gears in back, make the ratio higher (harder, or higher gears).  Then the opposite direction:  Smaller gears in front, and/or bigger gears in back, make the ratio lower (easier, or lower gears).  The trick, often, is finding a cost effective way to accomplishing what you need.

Before addressing exactly what to do based on the above flow charts, here are some things you need to know.

Bicycle Cassettes - Bike Rumor

Cassettes:

The cassette is the cluster of gears at the back — often called cogs.  The ratio span (or range) is the size difference between the smallest cog and the largest one.  The wider the difference, the greater the range of the cassette.  The two images shown here (from Bike Rumor) illustrate a narrow and a wide ratio cassette.

The Narrow ratio and the Wide ratio cassettes serve different purposes.  Small steps between cogs have the ability to keep a rider at the “perfect” cadence as terrain undulates.  Wide steps allow greater total range within the same number of cogs — which is needed, for instance, with 1X drivetrains.  The trade-offs are important, and your cassette choice should depend on many factors.

 

Of Note:  When choosing a cassette, think about the size of the smallest cog.  Fewer teeth mean smaller diameter; smaller diameters (front & rear) mean higher forces; which makes more load per tooth; and will wear-out faster.  In reaching for wider ratio spans, the industry is experimenting with 10 tooth small cogs.  They look good on paper, but they wear-out quickly.  Just something to be aware of when considering how you ride and what equipment to use.
Single Speeds and Geared Hubs:

For single speeds and geared hub bikes, ratio changes are pretty direct.  Change the cog in back, or the chainring in front, (or both), to achieve the desire ratio.  You can move the gear ratio up or down, but there is nothing practical you can do to change the overall ratio span (range) — unless you change the geared hub.

Chainrings for Junior Gears

Chainrings:

Chainrings are the gears near the pedals — often called sprockets.  Most modern bikes have 1, 2, or sometimes 3 chainrings.  These rings are typically separate components, that can be changed fairly easily, and they come in a wide variety of sizes — typically denoted by the number of teeth.  Like cassettes, the ratio span (or range) is the size difference between the smallest chainring and the largest one.

 

Your Body:

This is an important part of the equation, and often overlooked.

Think about it.  How often do you shift?  (Trick question, because if you’re not riding a single speed, the answer should be “nearly every time the terrain changes”.)

The body is a really cool machine capable of amazing things.  Yet, it functions best at some very specific sweet spots.  Take your bike fit for instance:  Get it wrong and your knees, hips or back will likely begin to hurt.

So, with respect to gears, we want to stay near the physiological optimums, which tend to be fairly narrow bands.  Here are a few body optimums to be aware of:

  • First,  Max Continuous Power Output (seated).  This is the condition where you make a reasonable amount of power for a long(ish) time.  It comes naturally, usually at a bit higher cadence, and in a very particular position on the bike.
  • Second,  Max Torque condition.  This is different in that it optimizes the amount of force on the pedals.  This is often the position when standing and pedaling somewhat slower than when seated.  The actual power out is more than the Max Continuous Power condition, but it’s shorter duration and you’re really not pedaling circles.
  • Third,  Maximum Efficiency (long distance cadence and bike position).  This is the way you do a very long ride – typically seated, typically lower cadence.
  • Finally,  The body is very sensitive to small changes.  Seat position, a grain of sand in your shoe, pedaling cadence, etc..  We see gearing charts showing ranges for 1X as “ALMOST” like 2X or 3X, but they fail to capture the essence of body sensitivity.  Like the grain of sand in your shoe, it’s tiny, but can make a big difference for enjoyment.

Why look at these?  If you know the conditions you body likes to perform well in, you can choose the right gears and an appropriate ratio span to get maximum speed / efficiency / and most of all enjoyment out of your bike.

 

This hits home when someone says “I really love this bike, but I can’t get the gearing right (with 1X.)  I keep buying smaller chainrings to climb, but then I’m wearing out small rear gears like crazy.”  What they’re really saying is the equipment on the bike does not match their physiological efficiency ranges for the ways and places they ride.  Changing to 2X usually increases both speed AND enjoyment.

Tying It All Together:

Results from the flow charts above boil down to 4 Scenarios.  The extent or importance of each scenario for you will depend on the significance of your perception of position along the Frequency Axis on the chart.  The more to the right or left that you place yourself, the more important the scenario.  Here are the 4 Scenarios with some rudimentary examples:

 

  1. You’re Good!  –  If you are “Probably Good” in both charts, Excellent!  Your ratios are right.
    Also, if the charts say  “Might Be Geared Too Low”  AND  “Might Be Geared Too High”,  you may actually have more gear range than needed, which is fine.  You’re probably good where you are.

 

  • Need Lower Gears  –  If Chart 1 says  “May Need Lower Gears”  AND  Chart 2 says  “Might Be Geared Too High”  … the span may be good, but you probably need a lower overall range.  In this case, look for a chainring set with fewer teeth.  The number of teeth fewer will depend on the strength of your answers from the flow charts.
    Cyclocross Example:
    You ride 46/36 chainrings, but need lower gears;  >  a change to 44/34 will accomplish that.

    Mountain Example:
    You ride an 11/34 cassette;  >  changing to an 11/36 will give you a little lower range.

 


 

  • Need Higher Gears   –  If Chart 1 says   “Might Be Geared Too Low”  AND  Chart 2 says  “Might Need Higher Gears”  … The span may be good, but you probably need a higher overall range.  In this case, look for a chainring set with more teeth.  The number of teeth more will depend on the strength of your answers from the flow charts.
    Road Example:
    You ride 50/34 chainrings, but need higher gears;  >  a change to 52/36 will accomplish that.

 


 

  • Need a Wider Total Ratio  –  If Chart 1 says  “May Need Lower Gears”  AND  Chart 2 says  “May Need Higher Gears”  … You probably need a greater overall gear range.  This is the situation when you sometimes feel over-geared (like when climbing and wish you had a lower gear), and sometimes feel under-geared (like spinning-out coming down a long sloper).  The solution is to increase your total ratio range with both higher and lower gears.

    You may also be span limited if one flow chart suggests a wider change, and the other chart says  “Probably Good”.  For instance, if Chart 1 says  “May Need Lower Gears”  AND  Chart 2 says  “Probably Good”.  This would indicate that a wider ratio (more low gearing, but keep the same high) is needed.

    If you need a wider ratio, there are several options:

    – Look for a chainring set with a greater difference between the largest sprocket and the smallest sprocket.

    Mountain Example:
    You ride 32/24 chainrings and need a wider ratio;  >  a change to 36/22 will give both lower and higher gears.

    – If you ride a single chainring (1X or 1-by) and need a wider gear range, consider a double.  Adding gears up front is the quickest way to drastically increase your total available ratio span.  (And to quit wearing out the small cogs on the cassette.)

    – Depending on the cassette you have, going to a wider ratio cassette (greater size difference between the smallest cog and largest cog) can give a wider total ratio.

    Mountain Example:
    You ride an 11/36 cassette;  >  a change to 10/42 will increase both the high and the low.

    – To accomplish your needed ratio changes, sometimes it requires more than one change — like chainrings and cassette.  Hopefully this is not the case for you, because lots of changes can become expensive.

 

 

Results from the flow charts above give a good indication of where you are with respect to where your bike is.  That’s usually pretty easy to understand.  However, finding the right equipment, knowing how much of a change is needed, staying within budget, etc. can be a little more complicated — especially when you want to change one end (say the low gears), but you don’t want to change the other end (high gears).

Gear Calculator Smart Phone App

To help with gear changes, if you’re analytically minded, try one of the FREE Gear Calculator apps available for your smart phone.  This one is pretty easy to use and kind of fun to play with.  Though it’s hard to know just how much of a change will make the right difference for you, it’s possible to get a good feel for it by comparing your riding as you change from one gear to another on your current bike, then using the Gear Calculator to see the mathematical difference.  Extrapolate that answer to the next gear or gears you need, and you’ll have some idea of how much higher or lower you need to go.  More importantly, you can make quick calculations that show if you can achieve the desired difference with just one change — like changing chainrings, or if you need to make multiple changes — like changing a combination of cassettes, chainrings, derailleurs, etc..

Because chainrings are easy to change and offer a quick method of changing ratios and ranges, we usually recommend starting there.  Look at what you have, look at possible options (for chainrings and cassettes), then make decisions based on what you want and what you can afford.

If the above does not make perfect sense, take these results to your local bike shop and have them help you.

 

A Quagmire of Considerations:

Here are some very important things to consider when changing gear ratios.  Sometimes it is not as easy as it should be:

Sprocket BCD Difference

1.  What minor changes can you make to get the desire result without requiring other, maybe drastic changes?

Example:  It may seem easy to change to a wide ratio cassette — but that may require a new rear derailleur to handle the big cassette.
Example:  A simple change of road rings from 53/39 to 52/36 can’t be done without a crank change from 130 BCD to 110 BCD, because the chainrings have a different bolt pattern.

2.  What are the limitations available for changes?

Example:  Smaller chainrings on a road bike may be logical, but check to see if the braze-on mount will allow the front derailleur to go low enough.  (Same with MTB direct mount.)

 

3.  Are there options for compatible components?

Example:  Shimano has made some weird bolt patterns on their cranks — so some options are not available.  If you have something weird like an 88 mm BCD, the options for change may be limited unless you purchase a different crank.

4.  Will the options you want, actually fit?

Example:  Some mountain bikes are made for particularly small chainrings.  If you try to mount larger ones, the rings may run into, or very close to, the chain stays.

5.  So many cost considerations.  Not only is there cost involved in making changes, there can be side effects that make it even more expensive.

Example:  Wide ratio cassettes seem like such a cool idea, but prices are oh so high!  And, if you suck it up and buy one looking for a little more top end, you may find the small cogs wear out fast and you’ll be stuck buying several.

Recommendations:

If your bike came stock with gears that don’t make sense for you, change them.

Usually the most effective approach to ratio changes are with chainrings.  They are typically less expensive than cassettes, and offer a wider variety of available options.

Case Study:  One racer had a SRAM 36/22 mountain combo on his race bike.  In a discussion after a race, we determined the ratio was too small.  We changed to a WickWerks 38/24 — and he placed better in his races.  Interestingly, this change also increased his pleasure in riding.

Case Study:  After studying the effects of the newer 11 speed cassettes, Katie Compton approached us about making a smaller chainring to match her physiology.  She changed from 44t to 42t to optimize her capability.  Please note that Katie is one of the fastest and strongest women on a ‘cross bike, so going smaller was counter to normal thought.  She, however, was smarter and saw the value for her situation, and it worked very well.

Single front chainrings are becoming quite popular — and we make them too.  Yet, even with wide ratio cassettes, they have trade-offs.  For some people they’re perfect.  For others, they give limitations, so we strongly recommend you consider carefully before just jumping in with the trend.  There is a wonderful draw for simplicity, but make sure it matches your riding.

Going along with the norm, or the trendy, or with what others may be doing is not always best.  ( I always admired those who rode 1X before it became popular; now I admire those that insist on 2X because it’s better for them. )  Maybe it’s the Rebel in me, or maybe it’s because  The best solution is always to look at how you perform and at how you like to ride.  It’s better for performance, and better for pleasure!

 

Enjoy the ride.